Photolysis of FeOH2+ and FeCl2+ in aqueous solution.: Photodissociation kinetics and quantum yields

Photodissociation of FeOH2+ and FeCl2+ complexes has been studied by pulsed laser spectroscopy (lambda = 347 nm) techniques. Transient bleaching of FeOH2+ was observed due to the dissociation FeOH+ --> Fe2+ + OH. (at lambda = 347 nm). The observed bleaching involved the photoreduction of the species FeOH2+ to iron(II) complexes. These latter species showed a much lower absorption. Concomitant formation of the Cl-2(.-) anion radical was observed due to the reactions FeCl2+ --> Fe2+ + Cl-. (at lambda = 347 nm) and C1' + Cl- - Cl-2(.-). The experimental findings allowed us to suggest a reaction sequence involving Cl-., Cl-2(.-), ClOH.- and OH. radicals. The quantum yields found by laser kinetic spectroscopy for FeOH2+ and FeCl2+ photodissociation were 0.21 +/- 0.04 and 0.5 +/- 0.1, respectively.